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Projeto de investigação
Flexible and High-Efficient Tandem Solar Cells endowed with Photonic Management for Space Application
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SCATMM
Publication . Alexandre, Miguel; Santos, Ivan M.; Martins, Rodrigo; Mendes, Manuel J.; Faculdade de Ciências e Tecnologia (FCT); Ubiquity Press
Ease-of-access to efficient and simple modelling software is fundamental for a broader adoption of these tools in academic, R&D or even industrial contexts. Here, we describe a user-friendly graphical user interface (GUI) termed SCATMM that effectively utilizes the well-known Scattering Matrix Method to determine the reflection, transmission, and absorption of arbitrarily thick stacks of planar layers. This capability connects with a wide range of applications, such as determining layer(s) thickness(es) by fitting with experimentally acquired spectra. This article describes the core development of the mathematical model, followed by a description of the main elements of the GUI. The model is validated through comparison with well-established FDTD simulations of a basic solar cell configuration, yielding a precise match between the resulting absorption spectra. For experimental comparison, the SCATMM tool was used to determine the thickness of a planar layer on a glass substrate, offering an additional example of the method’s application. Here, the determined thickness was paired to profilometry and SEM measurements, providing congruent values with less than 8% of discrepancy.
Physically-Deposited Hole Transporters in Perovskite PV
Publication . Akalin, Salih Alper; Erol, Mustafa; Uzunbayir, Begum; Oguzlar, Sibel; Yildirim, Serdar; Gokdemir Choi, Fatma Pinar; Gunes, Serap; Yilmazer Menda, Ugur Deneb; Mendes, Manuel J.; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; Wiley
Nickel oxide (NiOx) has received a lot of attention as an inorganic hole transport material (HTM) in perovskite solar cells (PSCs) during the last decade, owing to its high hole mobility, chemical stability, good optical transparency, and suitable energy levels that align with the valance band of the perovskite absorber methylammonium lead iodide (MAPbI3). This study explores Li and Mg co-doped NiOx thin films physically-deposited from developed sputtering targets obtained through cold isostatic pressing and sintering. After sputtering, the structural, elemental, morphological, optical, and electrical properties of the layers are investigated by XRD, XPS, SEM, AFM, UV–vis spectrophotometer, and Hall-effect; revealing that crystalline, homogeneous, and smooth films are obtained. In particular, improvements in mobility and conductivity values are observed with Li and Mg doping, which contribute to enhanced PSC performance when used as an HTM layer in the glass-indium tin oxide (ITO)/NiOx-based HTM/MAPbI3/phenyl butryic acid methyl ester (PCBM)/bathocuproine (BCP)/Ag architecture. The champion solar cell achieves PCE of 15.52%. In addition, the average values of all samples are boosted, JSC (from 13.21 to 15.60 mA cm−2) and FF (from 59.32% to 67.7%), relative to pristine HTM, resulting in a pronounced PCE increment of up to 30% with the HTM film sputtered by a single target of co-doped material.
Enhancing the efficiency of luminescent solar concentrators via soft colloidal lithography negative templating
Publication . Guerrero-Felix, J. G.; Correia, S. F. H.; Alexandre, M.; Gonzalez-Gomez, C. D.; Sencadas, V.; Fu, L.; Ruiz-Reina, E.; André, Paulo Sérgio B.; Moraila-Martinez, C. L.; Mendes, M. J.; Ferreira, R. A. S.; Fernandez-Rodriguez, M. A.; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; Elsevier
Building-integrated photovoltaics (BIPV) offers a sustainable pathway by seamlessly incorporating PV cells into architectural elements like façades and windows. In this study, we investigate the potential of luminescent down-shifting solar concentrators in combination with a nanophotonic light-trapping scheme to improve the optical-guiding capabilities and thereby enhance the energy conversion efficiency. We propose a novel cost-effective method to fabricate the photonic structures via soft colloidal lithography negative templating of thin films of TiO2 nanoparticles, successfully scaling the production to 11x11 cm2 glass windows. Through simulations and optical-electrical characterization, we demonstrate substantial improvements in energy harvesting for different angles of solar irradiation. We found increases in power output ranging from 57% for angles of incidence below 45° to above 100% for 60° thanks to the nanostructured TiO2 nanoparticles coatings added to a bottom down-shifting layer. This shows that such integrated approach can enhance both the efficiency and aesthetic appeal of solar solutions in urban environments, advancing the design of energy-efficient, sustainable buildings. Our methodology ensures consistent solar energy capture all year-round, for the relevant range of sunlight incidence angles, while preserving the transparency and multifunctionality of building elements.
Understanding the Potential of Light Absorption in Dots-in-Host Semiconductors
Publication . Alexandre, Miguel; Águas, Hugo; Fortunato, Elvira; Martins, Rodrigo; Mendes, Manuel J.; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; ACS - American Chemical Society
The outstanding physical properties of dots-in-host (QD@Host) hetero semiconductors demand detailed methods to fundamentally understand the best routes to optimize their potentialities for different applications. In this work, a 4-band k.p-based method was developed for rock-salt quantum dots (QDs) that describes the complete optical properties of arbitrary QD@Host systems, trailblazing the way for the full optoelectronic analysis of quantum-structured solar cells. Starting with the determination of the QD bandgap and validation against well-established literature results, the electron transition rate is then computed and analyzed against the main system parameters. This is followed by a multiparameter optimization, considering intermediate band solar cells as a promising application, where the best QD configuration was determined, together with the corresponding QD@Host absorption spectrum, in view of attaining the theoretical maximum efficiency (∼50%) of this photovoltaic technology. The results show the creation of pronounced sub-bandgap absorption due to the electronic transitions from/to the quantum-confined states, which enables a much broader exploitation of the sunlight spectrum.
Interfacial Engineering with One-Dimensional Lepidocrocite TiO2-Based Nanofilaments for High-Performance Perovskite Solar Cells
Publication . Panigrahi, Shrabani; Badr, Hussein O.; Deuermeier, Jonas; Jana, Santanu; Fortunato, Elvira; Martins, Rodrigo; Barsoum, Michel W.; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); ACS - American Chemical Society
The optimization of nonradiative recombination losses through interface engineering is key to the development of efficient, stable, and hysteresis-free perovskite solar cells (PSCs). In this study, for the first time in solar cell technology, we present a novel approach to interface modification by employing one-dimensional lepidocrocite (henceforth referred to as 1DL) TiO2-based nanofilaments, NFs, between the mesoporous TiO2 (mp TiO2) and halide perovskite film in PSCs to improve both the efficiency and stability of the devices. The 1DLs can be easily produced on the kilogram scale starting with cheap and earth-abundant precursor powders, such as TiC, TiN, TiB2, etc., and a common organic base like tetramethylammonium hydroxide. Notably, the 1DL deposition influenced perovskite grain development, resulting in a larger grain size and a more compact perovskite layer. Additionally, it minimized trap centers in the material and reduced charge recombination processes, as confirmed by the photoluminescence analysis. The overall promotion led to an improved power conversion efficiency (PCE) from 13 ± 3.2 to 16 ± 1.8% after interface modification. The champion PCE for the 1DL-containing devices is 17.82%, which is higher than that of 16.17% for the control devices. The passivation effect is further demonstrated by evaluating the stability of PSCs under ambient conditions, wherein the 1DL-containing PSCs maintain ∼87% of their initial efficiency after 120 days. This work provides not only cost-effective, novel, and promising materials for cathode interface engineering but also an effective approach to achieve high-efficiency PSCs with long-term stability devoid of encapsulation.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
3599-PPCDT
Número da atribuição
2022.01610.PTDC